that's great! but can u help me about my problem ....yours was all black..mine is all green & what is PRAM & SMC ? I'm new in computer

please help me....anyone there?[/quote[
PRAM = "Parameter RAM." Basically, it's where your computer stores various settings. Here's how to reset it:
http://support.apple.com/kb/HT1379
SMC = System Management Controller. This pages describes what it does and how to reset it:
http://support.apple.com/kb/HT1411
when i open photo booth and the screen is green, i can turn on any effects and the normal function results in this green screen. when i take a photo the green screen remains and thats my picture. has this happened to anyone else and how can i fix it?.my ichat webcam is functioning well...so the problem is take a photo...please help.....
Since you said your camera is working in iChat, resetting the PRAM or SMC probably wouldn't help. Instead, you can try deleting the Photo Booth preferences file (a file on your computer that stores certain settings for Photo Booth). To find this file, select "Go to folder..." from the Go menu in the Finder. Enter "~/Library/Preferences/" (minus quotes) and press return. Find this file, drag it to the trash, then empty the trash (click the trash icon in the Dock, then click the "Empty" button in the trash window).
Hope this helps. Post in this thread again if it works/doesn't work.